Twelve to fifteen million people in the United States suffer from diabetes mellitus (which is often, as herein, simply referred to as diabetes). Diabetes is a syndrome characterized by disordered metabolism and inappropriately high levels of blood glucose, i.e., hyperglycemia. Diabetes is classified into two distinct types. Type 1, also known as Insulin-Dependent Diabetes Mellitus (IDDM), is believed to be due to autoimmune destruction of beta cells in the pancreas, which are the only cells in the body that produce and secrete insulin. Type 1 occurs most commonly in juveniles but occasionally in adults. Type 2, also known as Non-Insulin-Dependent Diabetes Mellitus (NIDDM), is a milder form of diabetes that usually occurs in adults.
Up to about 10% of people with diabetes have type 1 diabetes, and are dependent on daily exogenous insulin. Insulin, a small protein, is degraded when taken orally; thus, it must be administered parenterally. Thus, most patients take insulin through injection. An increasing number are receiving insulin through a percutaneous pump, but this requires external apparatus that must be worn continuously. A fully implantable pump is also available, requiring monthly visits to a physician to refill the pump. An inhaled version of insulin is under development. Additional treatment options are needed.